Step 1Place an aluminum liner or foil beneath 2 gas burners and stand the eggplants, stem up, directly over a low flame. Allow the bottom of the eggplants to burn black until they look fully scorched. Lay the eggplants on their side. As soon as the area directly exposed to the flame turns soft, turn the eggplants slightly. Move them by grasping the stem. If there is no stem, use a pair of kitchen tongs--or two knives as levers--holding the eggplants from the top, nowhere else. Be careful not to burst the eggplants with the tongs. Keep doing this until both eggplants are fully roasted. This will be messy, but don't despair. The process should take about 20 minutes. You can also place the eggplants beneath a broiler, turning them, about 15 minutes.
Step 2Place the eggplants in a colander in the sink and run cold water over them, peeling the scorched outer skin under the flow of water. Shake off the water. Coarsely chop the eggplant flesh and set it aside in a bowl.
Step 3Heat the ghee or oil in a heavy-bottomed skillet over medium heat. Add the mustard seeds. As soon as they puff up, add the onions, ginger, garlic and turmeric. Fry this mixture until it begins to turn brown, stirring frequently, about 5 minutes. Add the green chiles, cilantro and tomatoes. Decrease the heat and cook for 10 minutes, stirring occasionally. Add the chopped eggplant and the salt, frying and stirring until very soft, about 20 minutes.
Step 4Serve hot, seasoned with lemon juice and garam masala and garnished with cilantro leaves.